A space maintainer is a general dental or orthodontic appliance that maintains a space left by a prematurely lost tooth or a space that will be filled by a tooth not yet erupted. Space maintainers are most commonly used when a deciduous tooth, such as a deciduous molar, is prematurely lost due to decay or trauma. The space maintainer prevents teeth adjoining the space formerly occupied by the lost tooth from tilting or otherwise moving into the space, and thereby interfering with the eruption of the new tooth. Also, the adult tooth may drift, and eventually erupt in the wrong position.
Space maintainers are usually made from plastic or stainless steel. Some can be removed, while others will be cemented into the mouth. Removable space maintainers will look much like a regular retainer. It may also have artificial teeth to fill in the spaces. Usually, this type of space maintainer is used for the sake of appearance as well as to allow permanent teeth to erupt.
If a child requires a fixed space maintainer, a metal band is put around teeth adjacent to the space that needs to remain open. The dentist makes an impression of the teeth in order to create the space maintainer. The band and the models are sent to a laboratory, where the retainer is constructed. The space maintainer is cemented into the child's mouth.
Space maintainers in use include:                A band-and-loop, wherein a stainless steel band is placed around the crown of an adjacent tooth. A loop is attached to the band, and stretched across the space, touching the other side of the open space that is preserved.        A lingual arch, wherein bands are wrapped around teeth on both sides of the mouth, with the connecting wire often bracing against the front teeth. The lingual arch wire is typically placed on the inside, or tongue side of the mouth, or along the bottom of a crown.        A distal shoe that is placed under the gum. If a six year molar has not erupted, this type of space maintainer may be used. Erupting teeth can be guided into position by this type of wire.        
Edentulous spaces may result from extraction, trauma, anatomy, or due to dental processes, such as preparation for the installation of dental implants. Bridges or pontics may be used to fill these spaces. If several teeth are missing, a partial denture may be used. In the case of each such device discussed above, the devices are relatively expensive to construct, costing several hundreds of dollars. Further, very few dental offices can construct these devices. Therefore, they are supplied by outside vendors, such as dental laboratories, who provide the devices for installation by the dentist or orthodontist.
There is a need for inexpensive devices to fill edentulous spaces. Such devices should be capable of construction by a dentist or orthodontist using tools and materials that are readily available at dental offices.